Our diverse team of engineers, designers, scientists and construction experts work to complete projects for the benefit of people and communities. Collectively, we have a reputation of solving tough, flow-related problems. We help our clients achieve positive results and responsible environmental stewardship. 

Our hydrology, hydraulics and fluids experts work with clients to address specific project goals, incorporating our multidisciplinary strengths to develop innovative approaches to test and analyze designs. We have completed countless projects for public sector clients such as major utilities, municipalities, municipal water and sewer districts—including those who serve large metropolitan areas—and many private-sector clients.

 

Recent Projects

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Between 1932 and 2010 the state of Louisiana has lost about 2006 square miles of land due to a combination of subsidence, sea level rise, and management of the Mississippi River. Computer models predict a further loss of 1800 to 4200 square miles in the next 50 years, amounting to 55% of the land in Plaquemines Parish and resulting in $300 million in annual economic damage. Following hurricanes Katrina and Rita, the Coastal Protection and Restoration Authority (CPRA) was formed as a single state entity with the authority to protect and restore the lands of coastal Louisiana.

The $50 billion coastal master plan includes restoration and risk reduction projects. The restoration projects include barrier island restoration, hydrologic restoration, marsh creation, ridge restoration, sediment diversion, and shoreline protection. The Barataria and Breton Basins have experienced some of the largest land loss—almost 700 square miles. Two sediment diversions are being designed, one for each basin. The sediment diversions connect the Mississippi River to the basins, allowing for the controlled diversion of up to 75,000 cfs of water and sediment to the Barataria basin and 30,000 cfs to the Breton basin.

The design and construction of sediment diversions on the scale proposed for Barataria and Breton is unprecedented, the results of which will rely heavily on the numeric and physical modeling required to design the major diversion features, including the inlet, conveyance, and outlet structures. Alden is constructing two 1:65-scale, live-bed physical models to test performance and effectiveness of the diversions.

Discover more:

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Clients and Alden Engineers discussing model at initial testing visit
Civil Infrastructure | Hydrology Hydraulics and Fluids
Mid-Barataria Sediment Diversion

Alden constructed two 1:65-scale, live-bed physical models to test performance and effectiveness of the proposed land rebuilding diversions on the Mississippi River.

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The Cedar Cliff dam and hydropower project is located approximately six miles from Cullowhee, in Jackson Country, North Carolina. The dam and hydroelectric facility is owned by Duke Energy and is located downstream of three other hydroelectric projects that are operated as a system.

The primary spillway includes a Tainter gate and the existing auxiliary spillway system includes two fuse plug sections (with different crest/activation elevations).  It was determined that the combination of the primary and auxiliary spillway systems were not adequate to safely pass the regulatory-increased Inflow Design Flood (IDF). The construction of a Hydroplus Fusegate system with six semi-labyrinth Fusegates in an enlarged auxiliary spillway channel was selected to increase spillway capacity to safely pass the new IDF which is now the full Probable Maximum Flood (PMF). 

Two reduced scale physical models were constructed to determine the required size of a ventilation system for the proposed Cedar Cliff Fusegates and headpond and tailwater levels at each Fusegate for flows up to the sixth Fusegate activating. The tailwater levels were required for design of the Fusegate ballast system.  

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Model testing looking upstream
Civil Infrastructure | Hydrology Hydraulics and Fluids
Cedar Cliff Spillway

Physical model study to determine hydraulic performance of a proposed auxiliary spillway system during flooding events

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In order to meet screen velocity requirements of the Clean Water Act 316 b rule, American Electric Power has investigated the possibility of replacing the Clifty Creek Power Plant traveling water screens with an array of cylindrical wedgewire screens in the cooling water intake forebay.  The site on the Ohio River experiences significant siltation, and there were concerns about associated vulnerability of the wedgewire screens. 

Alden performed flow modeling to evaluate this possibility, and provide possible solutions. The model scope included river flow both upstream and downstream of the intake structure and flow within the intake structure. To model the geometric details of the system accurately, a field survey conducted by Alden was performed prior to the flow modeling efforts. The flow study included 2D and 3D numeric modeling, as well as scale physical modeling.

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Field survey conducted prior to model testing
Civil Infrastructure | Hydrology Hydraulics and Fluids
Clifty Creek Power Plant Intake Modification

investigation of the hydraulic, thermal, and sediment dynamics within a cooling water intake forebay on the Ohio River, including both 3D numeric and physical modeling


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